An air pre-cleaner is disposed upstream of an air cleaner, and is generally used for removing impurities from intake air. A conventional air pre-cleaner includes a housing and an air exhaust pipe that is mounted in the housing.
Further, a drain valve is provided in a lower portion of the housing, and the drain valve is configured to drain impurities in intake air.
Because the air exhaust pipes of conventional air pre-cleaners have an elliptical shape, the air flow speed around the air exhaust pipe is so high that impurities cannot effectively be removed from the intake air.
Furthermore, the housing of the air pre-cleaner has a stepped portion where a sectional area of the housing increases instantaneously. Therefore, an eddy flow is formed in the stepped portion of the housing, so that air flow in the housing of the air pre-cleaner becomes irregular.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.